No power on from standby. Same with two PSUs. (No brand TV)

[goop]

I have two units of the same TV. One does not power up from standby (standby light is on), the other does. I switched the PSUs between them and the problem stayed on the same TV, so the PSU is okay (Megmeet MP116A rev 1.0. Photos on this thread).

I guess that means the problem is the logic board, which is a Cultraview CV181H-X-41C (a brief spec for the CV181H-X-40C here, the 41C is similar):


full size

Should I assume it's capacitors to blame?

The bunch of capacitors and inductors to the left are around TI TPA3110LD2 audio amp, so maybe unrelated.

The two near the middle are next to a panel voltage select jumper, two voltage regulators, and flash.

The two to the right are near the power input and two regulators.

The one near the VGA connector is next to an SG Micro SGM330A analog video switch.

What should I try?

[steviewonder]

Re: No power on from standby. Same with two PSUs. (No brand TV)

I would,with almost certainty,say it's the flash eeprom ic.
steve

[goop]

Re: No power on from standby. Same with two PSUs. (No brand TV)

Why do you say that?

[ReeceyBurger123]

Re: No power on from standby. Same with two PSUs. (No brand TV)

As its a umc chassis, the most common fault on these is the flash ic with the epprom on it going corrupt with age. Check the model of the tv and see if you can find a new flash chip thats been precoded.

[goop]

Re: No power on from standby. Same with two PSUs. (No brand TV)

What's UMC?

[stj]

Re: No power on from standby. Same with two PSUs. (No brand TV)

a tv make
http://www.umc-uk.co.uk/firmware.php

[goop]

Re: No power on from standby. Same with two PSUs. (No brand TV)

I see. It's not branded UMC, and actually the two TVs are each branded slightly differently, but if they all use the same Cultraview logic board their faults might be similar.

Is it possible to ascertain somehow that it's the flash?

Should it be possible to read and write the chip in-circuit?

Why would flash get corrupted so easily?

[gravesent]

Re: No power on from standby. Same with two PSUs. (No brand TV)

Are any of you able to give me the values of D13 / D15 located against the heatsink closest to the connectors on the edge, also Q15 and Q16? Any help is greatly appreciated!

[gravesent]

Re: No power on from standby. Same with two PSUs. (No brand TV)

Are any of you able to give me the values of D13 / D15 located against the heatsink closest to the connectors on the edge, also Q15 and Q16? Any help is greatly appreciated!

[budm]

Re: No power on from standby. Same with two PSUs. (No brand TV)

@gravesent: Which board and brand and model of what you are working on?
You are asking the same question on the MAGMEET power supply.
https://www.badcaps.net/forum/showth...331#post595331
https://www.badcaps.net/forum/showth...330#post595330

You should start a new thread and make sure to put make and model number on the thread.